DECLARE @userid int
DECLARE @customerid int

INSERT INTO [User] (Username, Password) VALUES ('username', 'password')

SET @userid = SCOPE_IDENTITY()

INSERT INTO [Customer] (UserID, FirstName, LastName, PhoneNumber, EmailAddress, ParentCustomerID)
VALUES (@userid, 'Test', 'Customer', '719-555-1234', 'test.customer@usoc.org', null)

SET @customerid = SCOPE_IDENTITY()

INSERT INTO [Address] (CustomerID, Line1, Line2, Line3, City, State, PostalCode)
VALUES (@customerid, '123 Test Street', '', '', 'Colorado Springs', 'CO', '90909')